EP2193515B1 - Security elements with tamper evident effect - Google Patents

Description

The present invention relates to a security element with tamper evident effect for a security paper or a valuable article and a method for producing the security element. By "Tamper Evident Effect" is meant that manipulation of the security element is obvious, i. That is, the security element can not be removed from the secured item without a visible or otherwise detectable change of the security item and / or the secured item.

The invention also relates to a security paper and a value document with the security element according to the invention and a method for producing the security paper and the value document. Furthermore, the invention relates to a transfer belt having a plurality of security elements according to the invention designed as transfer elements. Moreover, the invention relates to the use of the security element according to the invention for securing products of any kind.

Valuables, such as branded goods or documents of value, are often provided with security elements for the purpose of protection, which allow verification of the authenticity of the object of value and at the same time serve as protection against unauthorized reproduction. Valuables in the context of the present invention are in particular banknotes, shares, identity cards, credit cards, health cards, bonds, certificates, vouchers, checks, high-quality admission tickets, but also other forgery-prone papers, such as passports and other identity documents, as well as product security elements, such as labels, seals, packaging , high quality products, such as brand name products and the like. The term "value object" concludes in Following all such items, documents and product means. By contrast, "security paper" is understood to mean that the preliminary stage, which is not yet executable, is a value document.

Often attempts are made to manipulate security elements, for example, to detach them from the secured item in order to obtain an unsecured item or to use the security item for another item. It is therefore expedient to design security elements in such a way that such manipulations do not go unnoticed.

Security elements of this type are known. For example, the application discloses US 2005/0230961 A1 a Tamper Evident label that has vulnerabilities, such as perforation lines, fold lines, or cuts. The label is glued to an object to be secured and can no longer be removed intact, as it tears at the weak points in an attempt to pull it off.

EP 1 109 675 B1 discloses a security element having an adhesive layer for bonding to an article to be protected and a security print. The security print contains a pigment and a component that also dissolves in solvents that are able to dissolve the adhesive. When the security element is detached, the security pressure also dissolves and forms visible spots.

EP 1 569187 A1 discloses a security label having a film layer printed or printable on one side and having on the other side an adhesive layer for bonding to an article. Between the film layer and the adhesive layer is a print that upon removal of the label from the article, along with the adhesive layer, remains on the article.
WO 2005/119632 A1 discloses a security label having a cover layer, a contact adhesive layer, a transparent fluorescent ink printed film, and a strong adhesive layer, in that order. The label is adhered to an article to be protected, and the strong adhesive causes only the topcoat to peel off when the label is peeled off while the printed film remains on the article.

DE 102 51 781 A1 discloses a security element having a substrate with diffraction-optically effective surface structures which are partially filled with adhesive, whereby a reflection layer for the diffraction structures is unnecessary. The adhesive adheres the substrate to a carrier, resulting in the bonding plane both areas with adhesive (bonded areas) and areas without adhesive (unverklebte areas).

EP 0 253 089 B1 discloses a security document having a cover layer, a backing layer, and an intermediate layer therebetween that covers optical marks and differs in reflectivity or refractive index from the cover layer and the backing layer. Cover layer, carrier layer and intermediate layer are glued or welded together. Since the intermediate layer is provided only in certain areas, there are areas in which the cover layer and the carrier layer are directly connected to one another, so-called adhesive bridges. If the same materials are used for the cover layer and the carrier layer, the direct connection ensures a particularly good adhesion and in attempting to detach for destruction of the security markers in the vicinity of the adhesive bridges.

A disadvantage of the cited prior art is the low variability of the security elements in many respects. They require a largely defined structure, wherein the anti-tamper means are to be provided at a certain point. None of the disclosed security elements is universally applicable to the product security of any objects and provides protection against any type of unauthorized peel attempts, d. H. both mechanically and by a wide variety of solvents. In addition, they are sometimes expensive to produce or must be glued immediately after manufacture with the object to be protected.

Security elements according to the preamble of claim 1 are known from US 6,361,889 B1 and from the US 6129 975 A known.

Security elements with a tamper-evident layer in the form of an outer layer of the security element are known from the WO 2006/113178 A , of the US Pat. No. 6,670,008 B1 and from the WO 02/081585 A1 known.

Object of the present invention is to avoid the disadvantages of the prior art, at least in part.

It is therefore an object of the present invention, in particular, to provide a security element with anti-tamper means, ie means which make possible a possible manipulation, the manipulation protection means being intended to allow a high degree of variability. A high degree of variability means that the anti-tamper agents according to the invention should be provided anywhere in the security element can be. A specific structure of the security element should not be required.

The security element should further be tamper-resistant attachable to objects with arbitrary surfaces.

Furthermore, the security element should be easy to manufacture, be storable without altering the anti-tampering properties and show no change in anti-tampering properties even after prolonged use.
The security element should also be designed as a transfer element. In addition, it should be easily connected to the object to be protected.

It is also an object of the present invention to provide a security paper, a valuable article, methods of manufacturing the security element, the security paper and the valuables, and a security element transfer belt. A problem to be solved is also in the product protection of arbitrary objects.

The object is achieved by the security element having the features of the main claim. A security paper, a valuable article, methods for producing the security element, the security paper and the valuables and a transfer belt with the security elements according to the invention and the use of the security elements for product security are the subject of the independent claims. Specific embodiments of the invention are the subject of the dependent claims.

The security elements according to the invention typically have a layer structure of a plurality of layers, preferably of many layers. In principle, however, the "layer structure" can also consist of only one functional layer, for example a film with fluorescent pigments. Hereinafter, the present invention will be described with reference to security elements having a multi-layer structure, since the versatility of the invention becomes clearer on the basis of the multi-layer structure. However, the described structures and layer sequences are to be understood as illustrative only, not limiting, and the present invention is also applicable to any other security elements having other types of layers and layer sequences.

The core of the present invention is the anti-tampering layer. The tamper-resistant layer is a tacky layer that extends between two layers of the layer structure of the security element. It is therefore an intermediate layer within the layer structure of the security element.

The anti-tamper layer has substantially the same areal extent as the layers of the security element and has a substantially equal thickness over its entire areal extent. "Substantially equal thickness" means that variations in thickness are so small that a full-surface bonding of the adjacent layers, ie without disturbing non-adhesive areas, is ensured. In the direction of its areal extent, the anti-manipulation layer is composed of at least two, preferably a plurality of areas, which differ from each other in at least one physical property. For the purposes of this application, physical property is understood to mean a property that can be measured and thus within a possible range described physical theory and can be observed by an experiment. This understanding of a physical property corresponds to the definition given on the website "http://en.wikipedia.org/wiki/Physical_properties".

The areas may be arbitrarily shaped, for example forming a striped pattern, a pictorial representation or numeric characters. In the thickness direction, the physical properties of the individual regions are preferably identical in each case, ie. h., The physical properties of the anti-manipulation layer change in the surface direction, but preferably not in the thickness direction.

The physical properties in which the individual regions of the anti-tampering layer differ are, according to the invention, adhesiveness, solvent resistance, degree of curing and thermoplastic properties. Preferably, the layers differ in several physical properties simultaneously.

Adhesiveness is the adhesive force with which the anti-tamper layer adheres to the layers adjacent to it. Different solvent resistance means different solubility in organic, aqueous and / or other solvents. Different degree of cure means that the tamper-resistant layer has areas which are crosslinked to different degrees after irradiation and / or thermal treatment. The different curing usually means at the same time also a different adhesiveness, different thermoplastic properties and different solvent resistance.

The different properties in the surface direction can be achieved by the manipulation protective layer "patchwork-like" composed of different materials, for example, two or more adhesives of different water solubility, two or more adhesives of different solubility in protic and / or aprotic organic solvents, from a or more water-soluble adhesives in combination with one or more organic solvent-soluble adhesives, etc. A plurality of radiation-curable adhesives are used in common.

It should generally be noted that in addition to adhesives of different water solubility it is also possible to use adhesives with different dispersibility or else adhesives whose water solubility and dispersibility depend on the pH and / or the polarity of the adhesives.

The adhesives having different water solubility are advantageously selected from the group consisting of acrylate resins, urethane resins, maleate resins, synthetic resins, polyester resins and / or other carboxyl-functional resins, their saponified and / or esterified derivatives and / or hydroxyl-containing compounds. On the other hand, the adhesives having different solubility in organic solvents are preferably selected from the group consisting of cellulose derivatives such as nitrocellulose, ethylcellulose, cellulose acetopropionate and cellulose acetobutyrate, vinyl polymers, polyamides, polyurethanes, ketone resins, PET resins and / or synthetic resins.

In connection with the above statements on the solubility of the adhesives in certain solvents, it should be noted that also adhesives can be used with substantially equal solubility in a solvent, but different thermoplastic properties for the at least two regions of the anti-tamper protective layer according to the invention. The different adhesives of the at least two regions of the tamper-resistant layer differ in such a case at least by their thermoplastic properties, but not or not significantly by their solubility in a particular solvent.

Basically, the more different properties, d. H. different materials and / or different degrees of cure, are combined, the higher the security against unauthorized manipulation of the security element. It is therefore advantageous to combine several materials having different physical properties, for example, a material that is soluble in aqueous but not in organic solvents, a material which is soluble in certain organic but not aqueous solvents, and a radiation-curable material Material.

Areas of different adhesive force prevent mechanical removal of the security element, areas of different solvent resistance prevent detachment of the security element by solvents, differently strengthened areas or different thermoplastic areas prevent detachment of the security element by heating or by peeling. At least removal of the security element from the substrate is not possible without the manipulation being found in any way. Manipulation attempts always lead to a directly visually recognizable or otherwise detectable change of the security element and / or the substrate. "Change" in this application means the security element and / or the substrate are damaged in the removal attempt of the security element, for example by tearing, or the removal of the security element succeeds apparently, but it remains traces of the security element on the substrate back, either with the naked eye, but at least with suitable tools detectable are. Such traces could be dyes which are contained in the manipulation protective layer or at least in the areas of the manipulation protective layer with better adhesion, or IR or UV fluorescent dyes or thermochromic materials, the presence of which is recognizable only with suitable irradiation or temperature change.

As materials for the anti-tamper layer, thermoplastic, heat-sealable adhesive systems are preferably used, hereinafter referred to as "hot-seal adhesive". Heat sealability is not a mandatory condition, but it is preferred because the application of security features to articles to be protected by heat sealing is practically and procedurally relatively easy.

In the following, some embodiments of the present invention, their preparation, and preferred materials will be described in more detail.

According to a variant of the present invention, the anti-tamper protection layer is produced from a radiation-curable hot-seal adhesive.

When applying security elements using heat-sealable adhesives, at least one of the substrates to be bonded is coated with a solvent-borne polymer solution or an aqueous solution or dispersion of a polymer. After physical drying, preferably at elevated temperature, more preferably at about 60 ° C to 90 ° C, is a sealable composition which acts under pressure and elevated temperature, for example, about 100 ° C to 160 ° C, as an adhesive. The temperature at which the heat-sealing operation is performed will be referred to as "heat-sealing temperature" hereinafter. So-called hotmelt adhesives are applied without solvent or dispersion medium. After cooling, they form a solid coating, which acts as an adhesive on renewed heating and pressure.

According to the invention, hot-seal adhesives are preferably used to form the anti-tamper protection layer (s), in particular those which form substantially tack-free coatings after physical drying or after cooling (hotmelt adhesives) below the heat-sealing temperature, particularly preferably at room temperature.

In the context of the present invention, the term "essentially tack-free" also means substantially tack-free in the sense of a smooth, substantially non-sticky surface. The test can be carried out by the following test: coated pieces of film of about 100 cm ² are stacked and loaded with a weight of 10 kg and stored for 72 hours at 40 ° C. If the pieces of film can then easily be separated from one another without damaging the coatings, the coating must be regarded as essentially tack-free.

Tackfreiheit or Klebfreiheit below the heat sealing temperature or at room temperature is particularly important if the tamper protection layer is an outer layer of the security elements, and the security elements are not processed immediately after their preparation, but to be stored, resulting in winding of security element webs or requires stacking of security elements. By contrast, a non-tack-free manipulation protective layer as the outer layer would lead to a blocking of the security elements or the security element webs. If the anti-tampering layer is not an outer layer of a security element but an intermediate layer, tack-free adhesives can also be readily used.

The heat-sealable adhesive according to the first variant of the present invention contains at least one radiation-crosslinkable component. The presence of the radiation-crosslinkable component in the anti-tamper protection layer makes it possible to perform crosslinking by irradiation after application of the anti-tamper protection layer, preferably after physical drying of the anti-tamper protection layer. The networking creates a high-melting or infusible system. The achievable degree of crosslinking depends on the number of reactive groups in the crosslinkable component or in the crosslinkable components, the content and the nature of the photoinitiator or photoinitiators used and on the duration and intensity of the irradiation. The cross-linking improves the adhesion of the cross-linked areas of the tamper-resistant layer to the adjacent layers and increases the internal strength of the cross-linked areas of the tamper-resistant layer, while reducing their solubility and their thermoplastic properties, i. That is, the crosslinked areas of the tamper-evident layer can no longer or only with difficulty be softened or dissolved by solvents.

According to the invention, not the entire manipulation protection layer is uniformly crosslinked, but regions of different crosslinking, ie different curing, are produced. For this purpose, the manipulation layer is irradiated only in predetermined areas, while other areas remain unirradiated or may be exposed to less radiation. At the less or not irradiated and therefore less or not at all cured areas, the adhesive of the anti-tampering layer behaves like a conventional thermoplatic heat seal adhesive. He remains there at relatively low temperatures thermoplastic, water-sensitive and solvent-sensitive. In the cured areas, the adhesive is virtually non-thermoplastic and has very high solvent resistance and resistance to aqueous solutions.

Due to the different degrees of irradiation, areas with greatly differing hardness, thermoplastic properties, adhesion properties and resistance to organic solvents and to water are obtained in the direction of extent of the anti-tampering layer, and thus the conditions for tamper evident effects. If the radiation-crosslinkable anti-tampering layer or the radiation-crosslinkable heat-seal adhesive is dyed with dyes, colored or effect pigments (eg fluorescent, thermochromic) or the adhesive is mixed with mechanically detectable security features, such as magnetic particles, then the solvent or cooking water or In the case of mechanical stripping, ideally on the substrate, the pattern of the regions with good curing and thus correspondingly in daylight, under UV light or in the event of a temperature change visibly demonstrates the proof of a manipulation attempt or the mechanically provable evidence of a manipulation attempt. Such visually detectable and / or mechanically detectable security features in the anti-tamper protection layer may represent the only security features of the security elements according to the invention or serve as additional security elements, especially for the identification of the manipulation.

The radiation-crosslinkable adhesive systems used according to the invention for the manipulation protective layer are preferably crosslinkable by UV, IR radiation, short-wave visible light or electron radiation, more preferably crosslinkable by UV or electron radiation (UV / IR radiation and visible light are referred to as light radiation).

Cationic, anionic or radically crosslinkable systems can also be cured (crosslinked) by heating. In this context, a thermal activation (crosslinking) of radically or ionically curable systems is also spoken.

As radiation sources for crosslinking by radiation, conventional UV radiators (doped or undoped, eg Hg and Fe radiators) or preferably UV light-emitting diodes, electron radiators and excimer lasers are preferably used.

The radiation-crosslinkable heat-sealable adhesives are typically high molecular weight, at room temperature ideally solid, oligomeric compounds, eg. Acrylates dissolved or dispersed in water or organic solvents, d. H. emulsified or suspended. The solutions, emulsions, suspensions are applied to a layer of the security element structure either directly or after pressure pretreatment or after treatment of the backing layer of the tamper-evident layer with primer.

In general, cationic, anionic, nonionic and free-radical curing systems can be used. Particularly advantageous are acrylic acid esters, Vinyl ethers, epoxies and polyols. Under certain conditions, it is also possible to cure thermally, if appropriate only thermally. For photocuring, the heat-seal adhesive systems must contain photoinitiators, but not for electron-beam curing. Even with ionic curing systems that are thermally crosslinked, no photoinitiators are required. An advantage of missing photoinitiators is that subsequent post-crosslinking during use of the article is precluded.

Suitable radiation-curing systems are dispersions which are selected from the group consisting of aliphatic polyurethane dispersions, aromatic polyurethane dispersions, acrylates, anionic acrylate-modified polyurethane dispersions, polyurethane-polyether acrylates and mixtures thereof.

Particularly suitable are acrylated polyurethane dispersions. Examples of such acrylated polyurethane dispersions include DW7770, DW7773, DW7825, DW7772, DW7849 (UCB, Suface Specialties) and Actilane 340 epoxy novolac acrylate in butoxyethyl acetate (Akzo).
Further radiation-curable dispersions are, for example, NeoRad R-440 (NeoResins), NeoRad R-441 (NeoResins), NeoRad-R 445 (NeoResins), Laromer LR 8949 (BASF), Laromer LR 8983 (BASF), Laromer LR 9005 (BASF) LUX 101 UV dispersion (Alberdingk), LUX 241 UV dispersion (Alberdingk), LUX 308 UV dispersion (Alberdingk), LUX 352 UV dispersion (Alberdingk), LUX 370 UV dispersion (Alberdingk), LUX 390 UV dispersion ( Alberdingk), LUX 399 UV dispersion (Alberdingk), LUX 331 UV dispersion (Alberdingk), LUX 338 UV dispersion (Alberdingk), Halwedrol UV 95/92 W (Hüttenes-Albertus), Halwedrol UV 14/40 W (Hüttenes -Albertus), Halwedrol UV-TN 6711/40 W (Hüttenes-Albertus), Halwedrol UV 65/40 W (Hüttenes-Albertus), Halwedrol UV-TN 7561-3 / 40 W (Hüttenes-Albertus), Halwedrol UV-TN 7157/40 W (Hüttenes-Albertus) and Bayhydrol UV VP LS 2280 (Bayer).

Among the dispersions mentioned are anionic and nonionic dispersions. Most of these dispersions are aliphatic polyurethane dispersions (for example aliphatic polyester polyurethanes), but also aromatic polyurethane dispersions and copolymers (for example dispersions based on aliphatic polyurethane and acrylic ester copolymers), acrylates (acrylic ester copolymers ) and anionic acrylate-modified UV-curing polyurethane dispersions or polyurethane-polyether acrylates.

The solids content of the dispersion is preferably between 30% by weight and 60% by weight, preferably between 35% by weight and 50% by weight. However, by dilution, the solids content can be adjusted as needed.

Commercially available dispersions have a solids content of between 38% by weight and 51% by weight. Because of their ease of availability, such dispersions are preferred in the context of the present invention.

Initiation of photohardening generally requires photoinitiators. Therefore, at least the portions of the tamper-resistant layer which are to be light-cured by anionic, nonionic, cationic or radical mechanisms contain at least one suitable photoinitiator. The crosslinking can be started and controlled in a particularly simple manner by means of a photoinitiator. Preferred examples of such photoinitiators are Darocur 4265 (Ciba), Darocur 1173 (Ciba), Irgacure 500 (Ciba), Irgacure 184 (Ciba), Esacure KIP 100 F (Lamberti), Irgacure 2959 (Ciba), Irgacure 819 DW (Ciba) and Lucirin TPO (BASF), UVI-6992 (Dow Chemical Company), Omnicat 440 (IGM).

Particularly suitable cationic radiation-curing heat-seal adhesives contain epoxy-modified vinyl copolymers. An example of an epoxy-modified vinyl copolymer is UCAR VERR-40 (The Dow Chemical Company). A cationic curing UV lacquer system is ISS 1202 (Herberts).

The generation of regions of differential cure can be accomplished by irradiating the anti-tamper layer through a mask that absorbs or reflects the radiation, or by using a radiation source to "draw" the desired pattern of cured regions, ie one can selectively irradiate selected areas. A targeted irradiation is possible by means of laser or electron radiation, wherein the electron irradiation is preferably carried out through a mask. The curing then takes place only in the irradiated areas.
Alternatively, areas of different cure can be achieved by using two or more heat seal adhesives having different curing properties, depending on the desired cure pattern. Different curing properties can be achieved, for example, by applying different heat seal adhesives or by applying only a single heat seal adhesive, but in some areas contains a photoinitiator, not in other areas. For example, a photoinitiator-containing thermoplastic adhesive can be printed depending on the motif and, preferably, printed in perfect register therebetween or even in a thin application over the entire surface of the photoinitiator-free thermoplastic adhesive. When the photoinitiator-free layer is very thin (and radiation-curable), it becomes photoinitiator-containing Areas of overlapping areas with cured, while the remaining areas of the photoinitiatorfreien adhesive does not harden. An essential advantage of this design is that, in addition to the omission of a mask, post-crosslinking of the anti-tamper protection layer is not possible in the course of the later service life of the protected object. The variant, to provide photoinitiatorhaltige and photoinitiatorfreie areas and irradiate without mask, works in light curing, but not in curing by electron irradiation, since no photoinitiators are required for curing by electron irradiation.

The UV exposure can produce a mask via a targeted "flickering" of the spotlights. This requires a special ballast. Namely, the ballast has to be able to supply voltage periodically or aperiodically in response to a given strip-shaped motif in order to supply a UV lamp in a fast, alternating sequence with almost 100% and preferably almost 0%. You would then perceive a "flickering" for such a connected UV lamp. When using such a "mask" lamp, a relative movement of the lamp and the security element to be exposed is required. In practice, such a relative movement is achieved in that the material to be exposed moves when the "mask" lamp is stationary. But it is also conceivable, a hollow rotating cylinder with z. B. Stripe motif (alternating arrangement of UV-transparent and UV-opaque areas) to rotate a UV lamp. The UV lamp is then arranged stationary inside a rotary cylinder and is operated at a constant voltage.

Since security elements typically have a layer structure which, inter alia, contains layers which have certain light radiation (UV, IR, visible light) more or less strongly absorb and / or reflect, these layers can be used as "internal masks" if the exposure through the layer structure takes place (front-side exposure).

For example, so-called LEAD (Longlasting Economical Anticopy Device) security elements have a layer structure comprising a UV embossing lacquer layer (holographic security feature), layers containing dye-containing and pigmented printing inks, optionally embossing foils which absorb UV radiation, and a PVD layer (e.g. made of Al, Cr, Cu, bimetal, CS, metallic colors) which reflects UV radiation. In particular, black print or metallic layers, especially if several of these layers are superimposed in layer structure, cause a strong loss of radiation intensity. When irradiated through the layer structure penetrates at various points depending on the introduced radiation dose and the selected wavelength hardly radiation through the structure, the curing of the heat sealant adhesive is insufficient or can not be done at these points. These layers between radiation source and heat seal adhesive can thus serve as a mask to obtain a tamper evident effect. Of course, in this case, the tamper-evident motif can not be freely selected, but depends on the pattern that the reflective / absorbing substances form in the layer structure. At certain wavelengths, these mask layers can also have a certain transmittance and transmittance. In general, however, the mask layers described above in the wavelength range from 200 nm to 800 nm can be described as essentially opaque, since the transmission is below 1% in the entire wavelength range.

It is also possible to use a mask with a transparent lacquer or primer layer, which contains a high proportion of a radiation-absorbing or -reflective substance, for. As a UV absorber contains, apply. So you can bring in an invisible mask, and you do not have to match the visible motifs with the motif of the desired Tamper Evident effect. Depending on the distribution of the radiation-absorbing or -reflecting substances in the invisible mask layer, areas of different degrees of curing are obtained, and the mask is not recognizable in ordinary viewing.

Alternatively, of course, it is also possible to irradiate through an external mask.

The irradiation through the layer structure of the security element is possible irrespective of whether the manipulation protective layer is a radiation-crosslinkable intermediate layer in the layer structure or a radiation-curable heat-seal adhesive layer for bonding to a document of value or to another article to be protected.

Instead of through the layer structure of the security element, the irradiation can also be carried out from the heat seal side of the security element (backside irradiation). As a rule, an external mask must be connected upstream unless irradiated with a radiation source which can irradiate depending on the subject, such as laser and electron beams, or the manipulation protective layer is composed of different adhesive systems which have different curing properties depending on the subject. Different curing properties can result from the fact that the adhesive systems used a have different numbers of functional groups or that areas are provided with photoinitiator and areas without photoinitiator.

A suitable external mask (masking tape) is in the WO 2005/006075 A1 disclosed. The document specifically describes the mask in the context of electron irradiation. However, the mask and the irradiation method are generally applicable and also suitable for irradiation with light. The irradiation of the manipulation protective layer according to the invention can be carried out accordingly, as described in US Pat WO 2005/006075 A1 is described.

The manipulation protection layer according to the invention is an intermediate layer in the layer structure of the security element. It is preferred, but not mandatory, hardened by irradiation through the layer structure of the security element. When the tamper-resistant layer is the heat seal adhesive layer, it is preferably cured by back irradiation. If the security element contains a plurality of anti-tamper protection layers according to the invention, an intermediate layer and a heat-seal layer for bonding to the substrate, it makes sense to apply the interlayer from the front side of the security element, i. H. through the layer structure, and the bonding layer from the heat seal side, d. H. from the back of the security element, to be irradiated.

As an external mask for back irradiation of the security element according to the invention also the object to be protected can be used. This is possible in particular if the substrate, ie the object to be protected, is paper or plastic films. Such substrates often do not leave radiation over their entire area evenly, but have areas of better and poorer radiation transmission areas.

For example, paper often contains UV-absorbing substances, e.g. As TiO ₂ , or it is different thicknesses in different areas. As a result, when the security element is first adhered to the substrate and then irradiated through the substrate, different amounts of radiation are allowed to pass through the paper to the tamper-resistant layer, depending on the area, and differentially cured areas are thus produced in the tamper-resistant layer.

Such areas of different radiation transmission may also be produced in paper or plastic substrates by pigmented imprints, metallizations, local interlayers (eg, additional security elements) between the substrate layers, etc., which absorb and / or reflect the radiation used for curing. In particular, watermarks in papers offer themselves as a mask. If a watermark with a specific motif is deposited in the heat seal area of a security element, for example a LEAD strip, this leads to a hardening of the radiation-crosslinkable hot-seal adhesive in the form of the motif. It is ideal that the cure and thus the adhesion to the thinnest parts of the paper will be the best. As long as no manipulation takes place, the weak points in the paper are stabilized and protected by the security element. A manipulation or a detachment attempt leads to a destruction of the paper.

Another possibility is to include a paper primer, or any other varnish, or any color, that absorbs the curing radiation under the heat-sealable, heat-sealable adhesive and / or reflects to print in the form of a desired subject. This also gives you areas with different curing at a back exposure.

The same result is achieved if one applies the radiation-curing paper primer or the paint / the color not on the heat seal adhesive, but on the paper, preferably imprinted. Such prints, with the exception of the primer imprint, may also be provided on the opposite side of the paper or film (the side of the paper or film not adhered to the security element) in the area where the security element is applied ,

Each of these measures can be achieved by radiation from the back of the object to be protected forth a spatially resolved networking and thus a tamper evident feature can be created.

Especially with paper, there is another way to use the substrate itself as a mask. Wet paper is more transparent than dry paper, so moistening can increase the transparency of the crosslinking radiation. In order to motilize a radiation-crosslinkable heat-seal adhesive layer, the following procedure is suitable: a security element is connected to the substrate by heat-sealing, then the substrate (paper) is moistened in the form of a desired motif and finally radiation crosslinking is carried out. In the humidified areas is strongly cross-linked, in the non-humidified areas, however, much less strongly cross-linked, so that one obtains a manipulation protective layer according to the invention with areas of different degrees of crosslinking and therefore different physical properties. Particular aspects arise when using cationic curing adhesive as a radiation-crosslinkable layer, as a radiation-crosslinkable intermediate layer or heat-sealing layer. In contrast to anionic, nonionic and radical radiation curing, cationic radiation curing is a slower process, which continues even after the end of irradiation. While radicals are trapped in a short time, cationic radiation curing releases an acid that catalyzes the cross-linking reaction in the tamper-evident layer. Therefore, a cationic radiation-curable anti-tamper film can first be irradiated from the tamper-resistant layer side and immediately adhered to a substrate. The cationic radiation curing then proceeds even without exposure. The exposure prior to bonding from the coating side is advantageous since there is no stress on the substrate, for example paper, due to the crosslinking radiation, and also less radiation exposure of the material of the security element. The irradiation initiates the crosslinking reaction. At the time of application to the value substrate or other layers of the security element, for. B. when the cationic curing adhesive is an intermediate layer, it has not progressed so far due to the short period of time that the melting of the adhesive material would be difficult. Since the reaction continues without further measures on its own, one obtains the desired areas with different curing and different physical properties.

The cationic curing can also be partially stopped, which also results in areas of different adhesion and resistance to different solvents. On the one hand coated on a security element with a cationic curing heat seal adhesive and on the other hand, the object to be protected with a basic, for example amine-containing coating in motif form, irradiated the heat seal adhesive layer and then adheres the security element on the motif-coated object, so in the motif areas, the curing reaction is stopped and obtained in the manipulation protective layer areas of different curing.

A layer containing basic compounds in motif form may be provided on the heat seal adhesive layer instead of on the substrate to be protected. For example, a block-free layer with a high proportion of a melting base, preferably an amine, can be printed in pattern form. Alternatively, a radiation-absorbing or radiation-reflecting block-free layer can also be printed on the heat-seal adhesive in the form of a desired pattern. These layers form a mask that prevents curing of the anti-tamper layer in the covered areas when irradiated back.

As a further variant, motif layers with photolatent acids can be applied to cationically crosslinking heat-seal adhesive layers, motif layers with photolatent bases to anionically crosslinking heat-seal adhesive layers, and motif layers with free-radically forming compounds on radically crosslinking heat-seal adhesive layers. After bonding with the object to be protected and irradiation of the anti-tamper protection layer, crosslinking takes place only in the areas which are covered with the motif layers.

As discussed above, the tamper resistant layer may be located at various locations within the security element structure. Within the security element layer structure, the anti-tamper protection layer may comprise, for example, a primer layer or a print acceptance, Protective or laminating layer represent. In the case of such layers, there is the advantage that a radiation-crosslinkable, thermoplastic adhesive can be further processed immediately after cooling below the heat-sealing temperature or optionally after physical drying and can only be cured later in the manufacturing process of the security element, for example in an exposure step which occurs in any case. It is particularly preferred first to bond the security element to a valuable article substrate and then to cure all the radiation-crosslinkable layers together.

If the anti-tampering layer represents the security element and the valuable article connecting layer, the valuable article can be included in the production of the tamper protection layer, in particular if the valuable article is paper or plastic film. In principle, however, the inclusion of the substrate is possible with all substrate surfaces. To achieve a tamper evident effect, a radiation-crosslinkable heat-seal adhesive is provided both as a heat-seal adhesive outer layer of the security element and as a primer layer on the substrate. One of the layers is formed over the entire surface, the other layer has the shape of a motif. When joining the layers, different layer thicknesses result, which, when irradiated, leads to regions with different degrees of curing. Preferably, the layer should be significantly thicker with the subject, the thickness differences may not be so large that a full-surface bonding between the substrate and security element is no longer possible.

The advantage of priming the substrate with the radiation-crosslinkable heat-sealable adhesive prior to heat-sealing the security element, for example via a printing process, has the advantages that the substrate is superior to a pure one Heat seal process is wetted better and a thicker heat-sealable layer is obtained. Both improve the adhesion. Both the security element with the heat-seal adhesive outer layer and the substrate with the heat-seal adhesive primer layer is tack-free after physical drying of the adhesive and therefore windable, stackable, storable, but reactive up to the heat-sealing process. In heat sealing, the two thermoplastic, chemically virtually identical layers of heat seal adhesive and substrate primer merge and crosslink together during the subsequent irradiation. Heat-sealing adhesive and substrate primer are then virtually indistinguishable from each other and form a uniform layer, with motif-dependent priming, areas of different wetting and therefore different adhesion, in short, the condition for tamper evident effects are given.

A special case of substrate primers are layers with photolatent acids, photolatent bases and photolatent radical formers. Substrates with such reactive primers (initiators) are glued to manipulation protective layers which contain cationically crosslinking, anionically crosslinking or free-radically crosslinking components, and the layers are then irradiated For example, the cross-linking of the tamper-resistant layer takes place only in those areas that are bonded to substrate areas that have a primer layer, i. H. on which the required initiator is located.

It is essential that at least two adhesive systems are combined in such a way that at least two, preferably several, mutually alternating regions result in the direction of extent of the heat-seal adhesive layer, which have at least one physical property, such as adhesiveness, solubility in aqueous and / or organic solvents, thermoplastic properties, different from each other. Typically, different adhesive systems differ in more than one of the stated properties. Preferably, all adhesives used should be substantially tack free after physical drying or cooling below the heat sealing temperature.

• Miteinander kombiniert werden können beispielsweise zwei oder mehr Heißsiegelkleber auf wässriger Basis, wobei sich nach physikalischer Trocknung eine Manipulationsschutzschicht mit zwei oder mehr Bereichen mit zumindest unterschiedlicher Beständigkeit gegen wässrige Lösungsmittel ergibt;
• zwei oder mehr Heißsiegelkleber auf Lösungsmittelbasis, wobei sich nach physikalischer Trocknung eine Manipulationsschutzschicht mit zwei oder mehr Bereichen mit zumindest unterschiedlicher Beständigkeit gegen organische Lösungsmittel ergibt;
• mindestens ein Heißsiegelkleber auf wässriger Basis und mindestens ein Heißsiegelkleber auf Lösungsmittelbasis, wobei sich nach physikalischer Trocknung eine Manipulationsschutzschicht mit mindestens einem Bereich, der in wässrigen Lösungsmitteln, kaum aber in organischen Lösungsmitteln löslich ist, und mindestens einem Bereich, der in organischen Lösungsmitteln, kaum aber in wässrigen Lösungsmitteln löslich ist, ergibt;
• mindestens ein Heißsiegelkleber auf wässriger Basis, mindestens ein Heißsiegelkleber auf Lösungsmittelbasis und mindestens ein strahlenhärtbarer Heißsiegelkleber, wobei sich nach physikalischer Trocknung und Strahlenhärtung eine Manipulationsschutzschicht mit mindestens drei verschiedenen Bereichen, die sich mindestens hinsichtlich ihrer Löslichkeit in wässrigen und organischen Lösungsmitteln, in der Regel auch hinsichtlich Klebefähigkeit und/oder thermoplastischen Eigenschaften unterscheiden, ergibt; etc. Grundsätzlich sind beliebige Kombinationen der genannten Klebersysteme möglich.

Typically, aqueous based adhesive systems are less water resistant after physical drying, ie, less resistant to cold water, cooking water, soapsuds, etc., as solvent based (solvent based) systems, and solvent based adhesive systems are less resistant to physical drying against various organic solvents, eg. As acetone, toluene, etc., as adhesive systems on an aqueous basis. This circumstance is made use of according to the invention by forming the anti-manipulation layer from at least two different systems which form a pattern, for example a pictorial representation or a striped pattern. This results in a variety of combination options:

• For example, two or more heat-sealable adhesives may be combined with each other on an aqueous basis, resulting in a tamper-resistant layer having two or more areas with at least different resistance to aqueous solvents after physical drying;
• two or more solvent-based heat-sealable adhesives which, upon physical drying, provide a tamper-resistant layer having two or more regions having at least different organic solvent resistance;
• at least one aqueous-based heat-seal adhesive and at least one solvent-based heat-seal adhesive, wherein, after physical drying, a tamper-resistant protective layer with at least a region which is soluble in aqueous solvents but hardly soluble in organic solvents and at least one region which is soluble in organic solvents but hardly soluble in aqueous solvents;
• at least one aqueous-based heat-sealable adhesive, at least one solvent-based heat-sealable adhesive and at least one radiation-hardenable hot-seal adhesive, wherein, after physical drying and radiation curing, a tamper-resistant layer with at least three different areas, which is at least as regards their solubility in aqueous and organic solvents, as a rule also Adhesive and / or thermoplastic properties, results; etc. In principle, any combinations of the mentioned adhesive systems are possible.

The radiation-curable adhesives may be hot melt or solvent based or aqueous based adhesives.

According to a variant, the various heat-sealable adhesives are combined with one another such that regions of different properties are present only in the direction of extent of the anti-tampering layer, while the properties of a region in the thickness direction of the anti-tampering layer are constant.

According to a further variant, a hot-seal adhesive can be applied over the entire surface, ie have the same areal extent as the security element itself, and another, different heat-seal adhesive is applied as a motif on it. The type of heat seal adhesive (water-based, solvent-based, radiation-curing) is irrelevant, as long as the adhesive compatible with each other, ie with each other are glued. Care must be taken that the motif layer is thin enough to ensure full-surface bonding of the adjacent security element layer or substrate layer. If the full-surface layer and the motif layer are both radiation-curing, they combine on irradiation to form a layer which is homogeneous in each case in the thickness direction and has constant physical properties.
The application of the different heat-seal adhesives takes place pattern-like (motif-shaped) exactly in register or with slightly overlapping areas. The heat-seal adhesives are preferably applied in a printing process. For overlapping plots, the overlapping areas are thicker than the non-overlapping areas. An overlap of adjacent areas of different heat-sealable adhesives, without the full thickness bonding of the layers adjacent to the anti-tampering layer being affected by the thickness variation, is a juxtaposition in the area direction in the sense of the present invention.

Examples of suitable water-based or solvent-based heat-seal adhesives include polyesters, polyacrylates, urethane resins, methacrylates, isocyanates, blocked isocyanates, polyvinyl chlorides (PVC resins), polyvinyl butyrals (PVB resins), polyamides, ketone resins, maleate resins. Resins, dual-cure resins, ionomer dispersions, alkyd resins, phenolic resins, etc. may be mentioned.

The security elements according to the invention can be produced in the sequence of layers which they will later have on an article to be protected. However, they can also be prepared on a carrier layer, for example a plastic film, and if necessary by means of an adhesive layer, for example a manipulation protective layer according to the invention be transferred in the desired outline shape to the object to be protected. Such security elements are referred to as transfer elements, and since the carrier layer of the transfer element forms the uppermost layer during transfer, the layer structure of the transfer element must have the reverse layer sequence which is to be present on the article to be protected. The carrier layer can be removed after the transfer from the layer structure of the security element. In order to facilitate the detachment of the carrier layer, a separating layer can be provided between the carrier layer and the remainder of the security element. Alternatively, however, the carrier layer of the transfer element can also remain as a protective layer on the security element. Suitable materials for the backing layer are primarily plastics, in particular PET (polyethylene terephthalate), PBT (polybutylene terephthalate), PEN (polyethylene naphthalate), PP (polyproplene), PA (polyamide), PE (polyethylene). The plastics are generally used as a film, which may be monoaxially or biaxially stretched.

The transfer of transfer elements to a substrate, ie an object to be protected, and their connection to the substrate, as well as the combination of security elements with the "correct" layer sequence with a substrate, preferably by heat sealing. The layer of heat-seal adhesive is, for example, a manipulation protective layer according to the invention. To improve the adhesive force, a further adhesive layer can be applied between the anti-tamper protection layer and the remaining layer sequence of the security element, for example from the or one of the adhesives which form the anti-tamper layer, which is physically dried and subsequently cross-linked or precrosslinked by irradiation. Also on the substrate itself, such an adhesive layer can be provided for adhesion improvement.

If the heat-seal adhesive layer contains areas with radiation-crosslinkable components, the crosslinking can be carried out in different ways, depending on the type of radiation-crosslinkable components. One possibility is to crosslink the heat-seal adhesive layer or areas thereof by irradiation through the substrate of the article of interest after application of the transfer security element at elevated pressure and elevated temperature. For adhesive systems whose crosslinking progresses after initiation, the irradiation dose can be kept low or irradiation can be dispensed with altogether. For cationic crosslinking systems, the heat in the heat sealing process may be sufficient to initiate crosslinking that continues after the heat sealing process without irradiation.

The irradiation from the substrate side or the minimization or avoidance of irradiation advantageously reduces or avoids the radiation exposure of the material of the security element.

The transfer members according to the present invention are preferably provided as a ribbon having a plurality of transfer members. With regard to details for the construction of such transfer bands and the transfer of the transfer elements to be protected substrates is on EP 0 420 261 B1 directed.

The present invention also includes a security paper for the production of value documents, such as banknotes, checks, identity cards made of paper and / or plastic, documents, credit cards or the like, which is equipped with the security element according to the invention. As substrate material for the security paper every kind of paper comes into consideration, in particular cotton vellum paper. Of course, it is also possible to use paper which contains a proportion of polymeric material in the range of 0 <x <100% by weight.

Furthermore, it is conceivable in principle, although not currently preferred, that the security paper for the production of value documents a plastic film, for. B. a polyester film is. The film may also be monoaxially or biaxially stretched. The stretching of the film, inter alia, leads to it receiving polarizing properties that can be used as another security feature.
It may also be expedient if the substrate material is a multilayer composite which has at least one layer of paper or a paper-like material. Such a composite is characterized by an extremely high stability, which is for the durability of the paper or disk of great advantage.

It is also conceivable, however, to use a multilayer, paper-free composite material as the substrate material. These materials are also not preferred at present, but can be used with advantage in certain climatic regions of the earth.

All materials used as substrate material may have additives that serve as a mark of authenticity. It is primarily to think of luminescent, which are preferably transparent in the visible wavelength range and in the non-visible wavelength range by a suitable tool, for. B. a UV or IR radiation emitting radiation source can be excited to produce a visible or at least detectable with auxiliary luminescence.

The security element can basically be in any shape. In preferred embodiments, it has the form of a security band, a security strip, a label, a foil patch or other planar security element. The thickness of the security element is significantly influenced by the object to be protected. The security element preferably has a thickness of 1 μm to 100 μm, particularly preferably a thickness of 2 μm to 50 μm. These are the thicknesses of the security elements which are easy to handle when equipping security documents and security documents with security elements.
The substrate of the security element according to the invention is preferably flexible, since most items to be equipped with the security element, such. As banknotes or documents, are usually flexible. The objects to be protected are typically sheet-like articles made of paper-based and / or plastic-based materials, as already described above for the security paper according to the invention. Particularly preferred are valuable articles substrates which are at least partially permeable to UV radiation or electron radiation.

In addition to the use for the production of security papers and documents of value, the security elements according to the invention are generally suitable for securing products of any kind, for example for the purpose of marking branded articles or packaging.

The present invention will be further illustrated by means of figures. It should be noted that the figures are not to scale and proportions.

Fig. 1

eine Darstellung eines beispielhaften erfindungsgemäßen Sicherheitspapiers mit L-LEAD-Aufbau im Querschnitt;

Fig. 2

eine schematische, stark vereinfachte Darstellung eines erfindungsgemäßen Sicherheitselements mit einer Manipulationsschutzschicht als Zwischenschicht, einer Manipulationsschutzschicht als Außenschicht und mit einer internen Bestrahlungsmaske, im Querschnitt;

Fig. 3a

eine Draufsicht auf die interne Bestrahlungsmaske des Sicherheitselements von Fig. 2;

Fig. 3b

eine Draufsicht auf eine Manipulationsschutzschicht des Sicherheitselements von Fig. 2 nach Bestrahlung und Ablösung eines Teils des Sicherheitselements;

Fig. 4

ein erfindungsgemäßes Sicherheitselement wie in Fig. 2, aber ohne interne Maske und in Draufsicht bei Bestrahlung durch eine externe Maske;

Fig. 5

eine schematische, stark vereinfachte Darstellung eines erfindungsgemäßen Sicherheitspapiers im Querschnitt mit einem erfindungsgemäßen Sicherheitselement mit einer Manipulationsschutzschicht als Zwischenschicht;

Fig. 6

eine Darstellung wie in Fig. 5, aber mit einer zusätzlichen Manipulationsschutzschicht als Außenschicht und mit dem Substrat als Maskenschicht;

Fig. 7a

eine schematische, stark vereinfachte Darstellung eines weiteren, nicht erfindungsgemäßen Sicherheitselements mit einer Manipulationsschutzschicht als Außenschicht, im Querschnitt;

Fig. 7b

eine schematische, stark vereinfachte Darstellung eines weiteren, nicht erfindungsgemäßen Sicherheitspapiers mit dem Sicherheitselement von Fig. 7a, im Querschnitt;

Fig. 8

eine schematische, stark vereinfachte Darstellung eines weiteren, nicht erfindungsgemäßen Sicherheitspapiers mit erfindungsgemäßem Sicherheitselement mit einer Manipulationsschutzschicht als Außenschicht und mit einem geprimerten Substrat im Querschnitt;

Fig. 9a bis Fig. 9d

schematische, stark vereinfachte Darstellungen weiterer erfindungsgemäßer Sicherheitspapiere mit verschiedenen Varianten von erfindungsgemäßen Manipulationsschutzschichten, im Querschnitt; und

Fig. 10

die Übertragung eines erfindungsgemäßen Sicherheitselements von einem erfindungsgemäßen Transferband auf ein Substrat.

Show it

Fig. 1

a representation of an exemplary security paper according to the invention with L-LEAD structure in cross section;

Fig. 2

a schematic, highly simplified representation of a security element according to the invention with a tamper protection layer as an intermediate layer, a tamper protection layer as an outer layer and with an internal radiation mask, in cross section;

Fig. 3a

a plan view of the internal radiation mask of the security element of Fig. 2 ;

Fig. 3b

a plan view of a tamper protection layer of the security element of Fig. 2 after irradiation and detachment of a part of the security element;

Fig. 4

an inventive security element as in Fig. 2 but without internal mask and in plan view when irradiated by an external mask;

Fig. 5

a schematic, highly simplified representation of a security paper according to the invention in cross section with a security element according to the invention with a tamper protection layer as an intermediate layer;

Fig. 6

a representation like in Fig. 5 but with an additional anti-tamper layer as the outer layer and with the substrate as the mask layer;

Fig. 7a

a schematic, greatly simplified representation of a further, non-inventive security element with a tamper-evident layer as the outer layer, in cross section;

Fig. 7b

a schematic, highly simplified representation of another, not inventive security paper with the security element of Fig. 7a , in cross section;

Fig. 8

a schematic, highly simplified representation of a further, not according to the invention security paper with inventive security element with a tamper protective layer as an outer layer and with a primprimed substrate in cross section;

Fig. 9a to Fig. 9d

schematic, greatly simplified representations of further security papers according to the invention with different variants of manipulation protective layers according to the invention, in cross section; and

Fig. 10

the transfer of a security element according to the invention from a transfer tape according to the invention to a substrate.

Fig.1 shows an exemplary structure of a so-called L-LEAD security strip. A so-called L-LEAD security element typically consists of a carrier film 12, for example a PET film, optionally with a further layer structure 11, such as a pressure-receiving, protective or laminating layer, an embossing lacquer layer 13 with a holographic layer Security feature, a PVD layer 14, which is usually demetallized in part, a coating layer 15, for example, with black ink or metallic ink, a primer layer 16, which serves as a primer, optionally a further functional layer 17, for example with metallic or fluorescent imprint, and a heat seal adhesive layer 18 for connection to a substrate 2, for example a value document. Any other papers and films, composite structures or polymer surfaces can serve as a substrate. To improve the adhesion between security element 1 and substrate 2, the substrate may have an optional primer layer 19.

Security elements of this type with a carrier film 12 are preferably used in substrates with openings for covering the opening. By contrast, so-called T-LEAD security elements do not have the carrier foil 12 (and the optional layer structure 11), but are otherwise identical. T-LEAD security elements are typically applied to a substrate in a region that has substantially no opening.

The universal applicability of the present invention can be demonstrated on the multilayer security element shown. The thermoplastic, optionally radiation-postcrosslinking adhesive systems of the present invention can be used as pressure-accepting, protective and laminating layer 11, as adhesion promoter layer 16, as heat-seal adhesive layer 18 and also as substrate primer 19. For crosslinking the radiation-crosslinkable, optionally radiation-postcrosslinkable systems, the layers 14 and 15 can serve as masks when irradiated through the layer structure. One can provide in this way one or more manipulation protective layers and has possibilities of variation with respect to the position of the manipulation layers to the functional layers 13, 14, 15, 17. A particular advantage is that crosslinkable adhesive systems are not hardened within the layer structure of the security element during the manufacturing process of the security element, but only cooled to room temperature (hot melt adhesives) or physically dried (dispersions) and then processed immediately. Also, the heat-seal adhesive layer 18 need only be tack-free, but not crosslinked. Rather, all radiation-crosslinkable layers can be cured together after bonding to the substrate in a single irradiation process. Before bonding to the substrate, the security element can be stored for a long time without melting point change of the adhesive layers, preferably in the form of security-element tapes wound into rolls.

Fig. 2 shows in a highly simplified representation of a security element 1 with a layer structure 4 ', a functional layer 20, a manipulation protection layer 26, a layer structure 4 "and another manipulation protection layer 28. The layer structures 4' and 4" may each consist of one or more layers, such as functional layers It should be noted that in the figures, reference numerals 4 'and 4 "are used when a figure shows two partial layer constructions, and reference numeral 4 when one figure shows only one layer structure In the present embodiment, a partially demetallised PVD layer, the anti-tamper layer 26 consists of a pigmented layer of a UV-curable heat-sealable adhesive with photoinitiator, and the tamper-resistant layer 28 consists of two different heat sealable adhesives, each with fluorescent pigments Gel adhesives are printed in strip form alternately on the layer structure 4 ", wherein areas Solvent-based heat-seal adhesive and water-based heat-seal adhesive areas 28 'are selected, the pattern of stripes being selected for ease of illustration, but of course any other patterns are printable.

The security element 1 is irradiated through the layer structure 4 'and the functional layer 20 with UV radiation, wherein the functional layer serves as an internal mask. The internal mask 20 is in Fig. 3a shown in plan view. It has demetallized areas 20 'which are UV-transparent and metallized areas 20 "which are hardly permeable to UV, and therefore, in the case of UV irradiation of the layer 26 through the internal mask 20, only the areas in the layer 26 become 26 ', which are under the regions 20', are well cross-linked, while the remaining regions 26 ", which lie below the regions 20", are hardly cross-linked Fig. 3b shown.

If the security element is connected to a substrate (not shown) by heat sealing, it is no longer destructively detachable from the substrate after the tamper protection layer 28 has cooled. If one attempts to remove it with organic solvents, the areas 28 'dissolve, while the areas 28 "remain on the substrate, and the fluorescent pigments generate a stripe pattern under UV light Regions 28 "while the regions 28 'remain on the substrate, and the fluorescent pigments in these regions also produce a striped pattern on the substrate under UV light. Attempting to mechanically peel off the security element from the substrate will also be accomplished either by the tamper-evident regions 28 'and 28 "of the tamper-resistant layer 28 generates a visible under UV light stripe pattern on the substrate, or on the substrate is in Fig. 3b shown, which results from the fact that the non or fully cured areas 26 "of the tamper protection layer 26 can be removed together with the layers 20 and 4 'of the security element, while the hardened areas 26' of the tamper protection layer 26 together with the rest Layers of the security element remain on the substrate, so the manipulation is clearly recognizable.
In general, it should be noted that manipulation attempts on the z. B. arranged on the substrate security element according to the invention are always recognizable as such, regardless of whether the layers adjacent to the tamper protection layer identical or different physical properties, eg. B. adhesiveness to the tamper protection layer have. This means z. B. for in Fig. 2 shown layers 20, 26 and 4 "that due to the differently hardened areas of the tamper-evident layer 26 a peel (mechanical manipulation) is recognizable in each case, as a non-destructive detachment of the differently hardened areas of the tamper-evident layer 26 together with the adjacent layers 20 and layer This is true irrespective of whether the two layers 20 and 4 "adjoining the layer 26," z. B. with respect to their adhesiveness to tamper protection layer 26 show identical properties or not.

It goes without saying that the protection against tampering or manipulation protection can be further increased by virtue of the layers 20 and 4 "adjoining the anti-tampering layer 26 having different adhesive properties to the regions having different physical properties of the tamper protective layer 26. For example, the layer 4" may be joined to the hardened regions 26 'have a better adhesion Further, the adjacent layer 20 may be formed such that its adhesiveness to the non-cured areas 26 "is greater than to the hardened areas 26 '. This with respect to the Figures 2 and 3 statements made regarding the physical properties of the layers adjacent to the anti-tampering layer, in particular with regard to their adhesiveness, apply analogously to other embodiments described and shown in the present application and other physical properties of the layers adjacent to the tamper protection layer, eg for the layers 36 and 4 'and 4 "of Fig. 5 and Fig. 6 , but also for the layers 70 and 4 and 2 of Fig. 9 , It is of course always possible, on the basis of the properties differing in the direction of the surface of the anti-tampering layer, to further improve the protection against tampering by the targeted selection of the layers adjacent to the anti-tampering layer (materials, properties, etc.).

Fig. 4 shows a security element similar to the one in Fig. 2 illustrated security element, but without internal radiation mask 20, in plan view. In general, the same reference numerals in the figures mean the same or similar components. Instead of the internal mask 20, the tamper-resistant layer 26 in the security element 1 becomes Fig. 4 irradiated by an over the security element located external mask 30 with UV radiation. The external mask 30 is designed like the internal mask 20 in FIG Fig. 2 , ie there are UV-transmissive regions 30 'and UV-impermeable regions 30. As a result, in the anti-tamper-evident layer 26, the in Fig. 3b produced pattern generated.

Alternatively, 30 can be irradiated without preassay of an external mask. In this case, a radiation source must be used for the irradiation with which the desired cross-linking pattern, for example the shape of the regions 26 'in FIG Fig. 3b , "leaves". This is possible by laser irradiation or by electron irradiation. The likewise conceivable generation of exposure / crosslinking patterns by means of a UV lamp with a special ballast has already been explained above. In any case, the same result as in Fig. 3b basically without an external mask can be achieved.

Fig. 5 shows a security paper 10 with a security element 1, which is connected by means of a homogeneous layer 38 of a non-radiation-curable hot-melt adhesive to the security paper substrate 2. The security element 1 in addition to the heat seal adhesive layer 38 also has a tamper protection layer 36, which consists of a radiation-crosslinkable heat seal adhesive. In the in Fig. 5 In the embodiment shown, streak areas 36 'with photoinitiator and strip areas 36 "without photoinitiator alternate in the antiperspirant layer 36. When the security paper is irradiated, either from the front side (through the layer structure 4') or from the rear side (through the layer structure 4", the heat-seal adhesive layer 38 and the substrate 2), for example with UV radiation (without using a mask), only the regions 36 'are crosslinked with photoinitiator. The cross-linked regions 36 'are no longer thermoplastic and poorly soluble in solvents, while the non-cross-linked regions 36 "remain thermoplastic and solvent soluble, and therefore it is not difficult to separate the layer structures 4' and 4" in the plane of the antiperspirant layer 36. If the layer 36 is colored, a visible striped pattern remains on the manipulated security paper.

Fig. 6 shows a security paper of Fig. 5 Similar security paper 10 with a tamper-evident layer 36. Deviating from the security paper in Fig. 5 rejects the security paper from Fig. 6 However, another manipulation protection layer, namely the manipulation protection layer 48, with which the security element is bonded to the security paper substrate 2. The manipulation protection layer 48 consists of a radiation-crosslinkable heat-seal adhesive with photoinitiator, which physically dries without tack.

In the substrate 2, a metallized security thread 21 is embedded and a watermark 22 (shown greatly exaggerated) formed in the substrate.

During the production of the security element 1, the anti-tamper protection layers 36 and 48 are physically dried essentially until tack free. In this state, the security element can be stored without modification until it is used. The application to a valuable article, such as the illustrated security paper substrate 2, is accomplished by heat sealing by means of the tamper protective layer 48. Subsequently, from the rear side of the security element, that is to say through the substrate 2, surface is irradiated without using a mask, for example by means of UV radiation. As a result, the regions 36 'in the tamper-evident layer 36 are crosslinked, and crosslinking reactions also take place in the tamper-resistant layer 48, wherein the crosslinking has different strengths, since the substrate 2 acts as an internal mask. In the areas of the tamper-evident layer 48, which are irradiated by the thin substrate areas due to the watermark 22, a stronger cross-linking takes place than in the remaining areas. In the areas of the tamper protection layer 48, which are shielded by the metallized security thread 21, finds no networking at all instead, and the tamper-resistant layer 48 remains thermoplastic and soluble in solvents. Are the tamper evident layers 36 and 48 visible or invisible, e.g. B. fluorescent, colored, a detachment of the security element is immediately apparent or can be detected under suitable irradiation, since areas of the tamper protection layer remain on the substrate, while other areas are replaced with the security element or with parts of the security element.

Fig. 7a shows a security element 1 with a layer structure 4 and a tamper protection layer 58, which consists of a heat-seal adhesive with cationically curing components. The areas 58 'of the heat-seal adhesive contain a photoinitiator, but the areas 58 "do not, the areas 58' and 58" again being printed in an alternating fringe pattern on the layer structure 4. The tamper protection layer 58 will now, as in FIG Fig. 7a shown irradiated with UV radiation areally. As a result, the crosslinking reaction is initiated in the regions 58 'with photoinitiator. Subsequently, as in Fig. 7b shown, the security element 1 by heat sealing on a valuable substrate 2 transmitted. In this case, post-crosslinking of the manipulation protective layer 58 takes place, ie the crosslinking reaction in the regions 58 'does not come to a standstill, but continues to run to the end.

Fig. 8 shows a security element 1 after a heat-sealing process on a substrate 2. The security element 1 has a layer structure 4 and a tamper-resistant layer 68, which is also the heat-sealing layer. The anti-tamper layer 68 consists of a UV-curable hot-melt adhesive having an anionic polymerization mechanism. On the substrate 2 are printed strips 23 of a composition containing a photolatent base. After the heat sealing process the anti-tampering layer 68 is irradiated with UV radiation. This releases the photolatent base in the strip 23 and acts as an initiator for the crosslinking reaction. The areas 68 'of the tamper-resistant layer 68, which are in contact with the strip 23, are crosslinked, so that a tamper-resistant layer 68 is formed with alternating crosslinked areas 68' and uncrosslinked areas 68 " contain.
Conversely, in an analogously constructed security element with a cationically crosslinking manipulation protective layer, an already initiated crosslinking reaction can be terminated when the cationically curing heat-seal adhesive comes into contact with the photolatent base released by irradiation.

The FIGS. 9a to 9d show security papers 10, each having a substrate 2 (for example made of paper or plastic, with a homogeneous or heterogeneous surface), a layer structure 4 (embossing, metallization, primers, imprints, films, protective coatings, etc.) and a tamper protection layer 70. The security papers 10 differ in these manipulation protection layers 70 Fig. 9a For example, areas 7 with UV-curable heat-seal adhesive, areas 8 with solvent-based heat-seal adhesive, and areas 9 with water-based heat-seal adhesive are printed side-by-side in strip form. The areas may also overlap each other. The solvent-based and water-based heat seal adhesives need not be radiation crosslinkable. As a result of the change of the different heat seal adhesives, areas of different physical properties, such as a different solubility in aqueous and organic, result in the manipulation protective layer 70 Solvents and different thermoplastic properties.

Fig. 9b shows a representation like Fig. 9a However, the tamper-resistant layer 70 here consists of areas 8 'with a solvent-based first heat-seal adhesive and areas 8 "with a solvent-based second heat-seal adhesive The two heat seal adhesives have different solubilities in organic solvents.

Fig. 9c shows a similar representation as Fig. 9b However, the tamper-resistant layer 70 here consists of areas 9 'with a first water-based heat-seal adhesive and areas 9 "with a second water-based heat-seal adhesive The two heat-seal adhesives have a different solubility in aqueous solvents.

In the illustration in Fig. 9d The anti-tamper layer 70 also consists of two different heat-sealable adhesives, each of which can be radiation-curable or soluble in organic solvents or soluble in aqueous solvents. Here, however, one of the adhesives is printed over the entire surface of the layer structure 4 (area 5), while the other adhesive is printed on the area 5 as a strip-shaped motif (areas 6). For example, if both adhesives are radiation-curable compositions using the same mechanism, with region 5 containing no photoinitiator, but region 6 already, upon irradiation the subregions of layer 5 overlapping with motif 6 are cured.

Fig. 10 shows a transfer tape 3 according to the invention with a plurality of security elements formed as transfer element during the transfer on a substrate 2. The transfer belt consists of a carrier tape 40 on which a release layer 41, for example made of wax, is applied, which in turn is followed by the security element layer structure, in the reverse order as it should be later on the substrate , The layer of the layer structure 4 adjoining the separating layer 41 is preferably made of a thermoplastic material which is slightly less sensitive to heat than the separating layer 41. For applying the transfer element, the transfer belt 40, as in Fig. 10 shown with the hot-melt adhesive layer 88, which is inventively designed as a tamper-resistant layer, on a substrate 2, for example, a plastic card, placed and pressed. The pressing is done with a heated transfer punch 42 or alternatively with a transfer roller. Under the effect of pressure and heat, the hot-melt adhesive layer 88 bonds to the substrate 2, at the same time the separating layer 41 melts and makes it possible to remove the carrier layer 40. The connection to the substrate 2 and the separation of the carrier layer 40 take place only in the area regions exactly below the transfer punch remain in the non-heated surface areas of the layer structure 4 and the carrier layer 40 firmly connected to each other. The layer structure of the security element tears when removing the carrier layer 40 along the contour edges of the transfer punch 42. Therefore, the outline of the transferred to the substrate 2 transfer elements corresponds exactly to the outline of the transfer punch used.

Claims (12)

1. A security element (1) for bonding with a substrate (2), such as a security paper, a value document or other object, wherein
   the security element (1) has a layer structure with tamper protection means which ensure that the security element (1) after bonding with the substrate (2) is no longer removable from the substrate (2) without changing the security element (1),
   the tamper protection means are at least one tamper protection layer (26, 36) which is a layer on the inside of the layer structure of the security element and mutually bonds two layers of the security element, wherein
   the at least one tamper protection layer (26, 36) in the direction of the surface consists of at least two regions which inherently or after irradiation differ from each other with respect to at least one of the properties of adhesiveness, solvent resistance, degree of curing and thermoplastic properties, characterized in that the at least two regions of the tamper protection layer (26, 36) consist of at least two radiation-curing adhesives with different curing properties.
2. The security element according to claim 1, characterized in that the change of the security element consists in a mechanical damage of security element, or the change of the security element consists in color effects visible in daylight, in UV light or upon a temperature change.
3. The security element according to any of the claims 1 or 2, characterized in that at least one of the at least two regions of the tamper protection layer consists of a radiation-curing adhesive with photo initiator, and at least one of the at least two regions of the tamper protection layer consists of a radiation-curing adhesive without photo initiator.
4. The security element according to any of the claims 1 to 3, characterized in that the at least one radiation-crosslinkable adhesive is selected from the group consisting of cationically crosslinkable adhesives, anionically crosslinkable adhesives, non-ionically crosslinkable adhesives and radically crosslinkable adhesives, preferably from acrylic acid esters, vinyl ethers, epoxides or polyols.
5. The security element according to any of the claims 1 to 4, characterized in that the tamper protection layer has at least one radiation-crosslinkable adhesive, and that in the direction of the thickness of the security element a mask layer is arranged, wherein said mask layer covers one or several partial regions of the tamper protection layer and is capable of absorbing and/or reflecting radiation of a wavelength at which the radiation-crosslinkable adhesive is crosslinkable.
6. The security element according to claim 5, characterized in that the mask layer is a partially demetalized metalization layer, a print of metallic ink, a print of a printing ink containing radiation-absorbing and/or radiation-reflecting substances, a lacquer layer containing radiation-absorbing and/or radiation-reflecting substances, or a combination thereof.
7. The security element according to any of the claims 1 to 6, characterized in that at least one of the at least two regions of the tamper protection layer contains at least one compound selected from the group consisting of dyes and fluorescent and/or thermochromic effect pigments.
8. A security paper for manufacturing security documents or value documents, or a value document, characterized in that it is equipped with a security element according to any of the claims 1 to 7.
9. A method for manufacturing a security element (1) for bonding with a substrate (2), such as a security paper, a value document or other object of value, wherein
   the security element (1) has a layer structure and after bonding with the substrate (2) is no longer removable from the substrate (2) without changing the security element (1), and
   the security element (1) is equipped with at least one tamper protection layer (26, 36) containing in the direction of the surface at least two regions which inherently or after irradiation differ from each other with respect to at least one of the properties of adhesiveness, solvent-resistance, degree of curing and thermoplastic properties, and
   the tamper protection layer (26, 36) is formed as a layer on the inside of the layer structure of the security element (1), characterized in that the at least two regions of the tamper protection layer (26, 36) consist of at least two radiation-curing adhesives with different curing properties.
10. The method for manufacturing a security paper or a value document according to claim 8, characterized in that a security-paper substrate or a value-document substrate is equipped with a security element according to any of the claims 1 to 7.
11. A transfer band having a multiplicity of security elements according to any of the claims 1 to 7 to be transferred to a substrate, such as a security paper, a value document or other object of value.
12. Use of a security element according to any of the claims 1 to 7 or of a security element manufactured according to claim 9 for product securing of goods of any kind.

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